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<article xmlns:xlink="http://www.w3.org/1999/xlink">
  <front>
    <journal-meta>
      <journal-title-group>
        <journal-title>R. A. M. Aragon);</journal-title>
      </journal-title-group>
      <issn pub-type="ppub">1613-0073</issn>
    </journal-meta>
    <article-meta>
      <title-group>
        <article-title>Detecting Zero-Day Vulnerabilities in CMS Platforms: An In-depth Analysis Using DeepLog</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Alberto Schiafino</string-name>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Matteo Reina</string-name>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Ricardo Anibal Matamoros Aragon</string-name>
          <email>ricardo.matamoros@socialthingum.com</email>
          <xref ref-type="aff" rid="aff0">0</xref>
          <xref ref-type="aff" rid="aff2">2</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Alessandro Solinas</string-name>
          <email>alessandro.solinas@socialthingum.com</email>
          <xref ref-type="aff" rid="aff1">1</xref>
          <xref ref-type="aff" rid="aff2">2</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Francesco Epifania</string-name>
          <email>francesco.epifania@socialthingum.com</email>
          <xref ref-type="aff" rid="aff2">2</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Engitel S.p.A.</string-name>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Milan</string-name>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Italy</string-name>
        </contrib>
        <contrib contrib-type="editor">
          <string-name>Anomaly detection, Content Management Systems, Cybersecurity</string-name>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>Department of Computer Science, University of Milano Bicocca</institution>
          ,
          <addr-line>Milan</addr-line>
          ,
          <country country="IT">Italy</country>
        </aff>
        <aff id="aff1">
          <label>1</label>
          <institution>Politecnico di Milano</institution>
          ,
          <addr-line>Milan</addr-line>
          ,
          <country country="IT">Italy</country>
        </aff>
        <aff id="aff2">
          <label>2</label>
          <institution>Social Things S.r.l</institution>
          ,
          <addr-line>Milan</addr-line>
          ,
          <country country="IT">Italy</country>
        </aff>
      </contrib-group>
      <pub-date>
        <year>2023</year>
      </pub-date>
      <volume>000</volume>
      <fpage>0</fpage>
      <lpage>0002</lpage>
      <abstract>
        <p>In cybersecurity, protecting IT infrastructures from potential threats is one of the most pressing and intricate challenges. Over recent years, we have witnessed an exponential surge in techniques aimed at enhancing defense processes against attacks orchestrated by malicious users. Zero-day attacks are among the most insidious and damaging types of attacks. A Zero-Day attack exploits software vulnerabilities that are unknown to manufacturers or the general public. Due to their concealed nature, these vulnerabilities pose a particularly severe threat: anyone who becomes aware of them before the manufacturers can exploit them, launching attacks with a high likelihood of success since there are no existing solutions or patches to counteract them. Given the importance of preventing and detecting such attacks, we propose an innovative approach based on Deep Learning techniques in this paper. The goal is to conduct anomaly detection analysis on system logs of a Content Management System (CMS) platform. To achieve this, we utilized an algorithm known as DeepLog, which leverages Long Short-Term Memory (LSTM) neural networks to identify patterns in the sequential nature of the logs.</p>
      </abstract>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>-</title>
      <p>CEUR
ceur-ws.org</p>
    </sec>
    <sec id="sec-2">
      <title>1. Introduction</title>
      <p>
        Cybersecurity has become one of the primary concerns in the contemporary technological
landscape [
        <xref ref-type="bibr" rid="ref1">1</xref>
        ]. Cyberattacks have become increasingly sophisticated and harmful with the
evolution of technology and network expansion [
        <xref ref-type="bibr" rid="ref2">2</xref>
        ]. In particular, Zero Day attacks stand out
as one of the most insidious threats in the field of cybersecurity [
        <xref ref-type="bibr" rid="ref3">3</xref>
        ].
      </p>
      <p>A Zero Day attack exploits vulnerabilities not yet known to the public or the software
manufacturer, meaning that, at the time of the attack, there is no solution or patch to address the
vulnerability, leaving the software highly vulnerable. The concealed nature of these attacks
makes them especially dangerous, as attackers can exploit them knowing there are no ready
defenses to stop them.</p>
      <p>
        In this context, the analysis of system logs becomes crucial. Logs record all activities occurring
within a system and can provide valuable insights into anomalous or suspicious behaviors.
However, given the vastness and complexity of the recorded data, manual analysis becomes
unfeasible. Adopting automated techniques, such as those based on Deep Learning, is essential
to understand the logs’ nature and detecting potentially distrustful activities [
        <xref ref-type="bibr" rid="ref4 ref5">4, 5</xref>
        ]. Furthermore,
log data are unstructured and can vary in the format or semantics from system to system [
        <xref ref-type="bibr" rid="ref6">6</xref>
        ].
This diversity poses an additional challenge for efective log analysis. In the existing literature,
various approaches employ deep learning (DL) models, as discussed in [
        <xref ref-type="bibr" rid="ref7">7</xref>
        ]. These approaches
range from simple architectures such as Multi Layer Perceptron (MLP) which are often
outperformed by other structures, to Convolutional Neural Networks (CNN) that extend the MLP
framework with the addition of convolutional and max pooling layers, enabling the model to
capture more complex patterns, while reducing the model’s dimension. The most common
approach is the use of Recurrent Neural Networks (RNN) because they employ a feedback
mechanism that retains their states over time, enabling the learning of sequential patterns in
the input data. Our approach suggests using an algorithm known as DeepLog [
        <xref ref-type="bibr" rid="ref6">6</xref>
        ], which has
garnered recognition as one of the best-performing models in the domain of log analysis. It
harnesses the power of Long Short-Term Memory (LSTM) neural networks, which possess a
recurrent architecture specifically designed to analyze time series data, such as system logs.
LSTMs excel in their ability to remember and recognize long-term patterns within data. The
DeepLog algorithm follows a proactive strategy by training the neural network on ”normal”
logs, allowing it to learn the standard behavior of a system. Once trained, the model can
continuously monitor real-time logs, promptly detecting any deviations from the established
normal behavior. This capability makes DeepLog well-suited for the early detection of potential
Zero Day attacks, which is paramount in today’s ever-evolving cybersecurity landscape. In light
of these considerations, the choice to leverage DeepLog for log analysis is not only logical but
also strategically sound. Its ability to tackle the challenges posed by unstructured and diverse
log data, coupled with the power of LSTM networks, positions DeepLog as a potent tool in the
ongoing battle against sophisticated cyber threats, including Zero Day attacks. Implementing a
system based on DeepLog within a Content Management System (CMS) platform ofers several
advantages [
        <xref ref-type="bibr" rid="ref8 ref9">8, 9</xref>
        ]:
• Proactive Detection: DeepLog can identify anomalies in real-time, allowing for a swift
response to potential threats.
• Adaptability: The system can adapt to new norms thanks to machine learning, reducing
the risk of false positives.
• Scalability: The Deep Learning-based approach can handle large volumes of data, making
it ideal for large-scale CMS platforms.
      </p>
      <p>
        In formal terms, the research question is posed as follows: Is it feasible, through the use of
advanced Artificial Intelligence (AI) algorithms, to devise a mechanism capable of conducting
anomaly analysis on the log records of a CMS [
        <xref ref-type="bibr" rid="ref10">10</xref>
        ] and, upon detecting suspicious activities,
promptly notify the CMS administrators concerning potential vulnerabilities related to Zero
Day attacks?.
      </p>
      <p>In the subsequent sections of this article, we will illustrate the use case related to the CMS named
”Spin&amp;Go Brainy” developed by Engitel Srl. Following that, we will present the log analysis
methodology based on DeepLog, describing the structure of the model and its implementation.
Subsequently, the obtained results will be showcased and discussed. In conclusion, we will
introduce a dashboard representation method to provide visual insights into the logs examined
within the CMS.</p>
    </sec>
    <sec id="sec-3">
      <title>2. Spin&amp;Go Brainy: An Innovative CMS</title>
      <p>
        Within the context of this article, the application case under examination pertains to the platform
”Spin&amp;Go Brainy”, conceived, produced, and marketed by Engitel S.p.A [
        <xref ref-type="bibr" rid="ref11">11</xref>
        ]. This platform has
been designed to assist clients and stakeholders in the development and continuous optimization
of their online portals and related activities. It is an integrated and well-structured system,
enriched by a series of modules operating synergistically, founded on Artificial Intelligence.
These modules aim to guide both decision-makers and content creators through the phases of
design, development, and consistent updating of web services, including those highly specialized.
Furthermore, the platform promotes technological transfer and digital transformation, aligning
with the vision of Industry 4.0 [12].
      </p>
      <p>A CMS, or Content Management System, is software designed to manage the contents of
a website in an intuitive and rapid manner, eliminating the need for specific programming
expertise [13].</p>
      <p>Spin&amp;Go Brainy, a brainchild of Engitel, is recognized as one of the most eficient CMSs available
on the market, thanks to its unparalleled stability and versatility. It has been developed using
Microsoft’s .NET technology but is designed to interface with any other computer system.
Its applicability is vast, attributable to its modular nature and the numerous functionalities that
have been integrated over the years. Spin&amp;Go Brainy is employed in a variety of contexts, such
as institutional websites, editorial platforms and blogs, e-commerce solutions, showcase sites,
applications, document archives, online communities, and smart networks. Engitel’s Spin&amp;Go
Brainy CMS platform ofers a range of advanced features tailored to modern digital needs:
• Editorial Tools: Advanced functions like cut &amp; paste from Word, time-deferred content
publication, and integration of various data types ensure streamlined content
management.
• Image Handling: Automatic resizing eliminates the need for multiple image formats,
simplifying media management.
• SEO Optimization: Features like automatic metadata association and intelligent URL
management enhance site visibility on search engines.
• Data Protection: The platform ensures user data ownership, aligning with data protection
best practices.
• Document Management: An intelligent repository system allows for eficient content
storage and retrieval.
• Notifications: Automated email alerts notify users about new content, ensuring timely
updates.
• Event Management: An interactive calendar feature allows for detailed event planning
and geolocation.
• Newsletters: Direct back-ofice newsletter creation with customizable templates facilitates
efective communication.
• User Management: Comprehensive user registration tools, including customizable forms
and reserved areas, enhance user experience and data security.</p>
      <p>In essence, Spin&amp;Go Brainy ofers a comprehensive, user-friendly, and SEO-optimized CMS
solution, catering to diverse digital content needs.</p>
    </sec>
    <sec id="sec-4">
      <title>3. Anomaly detection with DeepLog</title>
      <sec id="sec-4-1">
        <title>3.1. Log extraction</title>
        <p>To extract logs successfully, we employed Osquery [14]. This instrument allows its users to
obtain low-level information directly from the operating system (OS), such as data from the
system registry, information on executing processes, and active network connections. These
gathered data can be subsequently used to detect anomaly behaviors and possible security
vulnerabilities. Osquery follows a client-server architecture, where the Osquery client executes
queries directly on the operating system and sends the results to the Osquery server for further
processing and analysis. After acquiring the information about Osquery, the development
demo project within the Google Cloud Platform (GCP) Compute Engine service created virtual
machine instances [15]. The assigned VM was named ”crdhost”. Once the logs have been
extracted, the work aims to perform an Anomaly Detection Analysis. Specifically, the purpose
is to create a multidimensional time series that represents sequences of actions a user performs.
An automated Python script executes the Osquery query every ten minutes, and the data is
saved in a BigQuery [16] table within the GCP.</p>
      </sec>
      <sec id="sec-4-2">
        <title>3.2. Preprocessing</title>
        <p>To embark on the process of modeling our log data using the sequential structure of LSTM (Long
Short-Term Memory), a preliminary and crucial step involves the parsing of this data into a more
structured and coherent format. This transformation is imperative to ensure that the data is
conducive for the intricate operations of LSTM, which thrives on structured sequences. To elucidate
with a tangible example, consider the log messages such as
”idchannel=1&amp;idcontent=143547&amp;idmaster=143547&amp;” in ”idchannel=*,idcontent=*, idmaster=*,...”. This transformation involves the
removal or anonymization of specific log values, retaining only the log keys. Such a procedure
ensures that the data retains its structural integrity while obfuscating specific values, making it
more amenable for sequential modeling.</p>
        <p>Once this transformation is achieved, the next phase involves the grouping of these logs. We
aggregate them into sequences comprising 20 units each. These sequences serve a dual purpose.
Firstly, they act as the foundational input for our DeepLog model. Secondly, they set the stage
for the prediction task where the model endeavors to predict the 21st log entry based on the
preceding sequence.</p>
        <p>The prediction mechanism of DeepLog is designed to ofer  possible options for the 21st log
entry. This is where the anomaly detection comes into play. If the actual 21st log entry, derived
from the real-world data, does not align with any of the ’k’ options provided by DeepLog, it
is flagged as an anomaly. Such a mechanism is invaluable in scenarios where monitoring and
early detection of irregularities are paramount. By leveraging the capabilities of LSTM and the
structured approach of DeepLog, we aim to create a robust system that can not only predict but
also identify potential anomalies in vast streams of log data.</p>
      </sec>
      <sec id="sec-4-3">
        <title>3.3. Model architecture</title>
        <p>The DeepLog architecture is divided in three main components: the log key anomaly detection
model, the parameter value anomaly detection model, and the workflow model to diagnose
detected anomalies.</p>
        <p>
          During training, the model learns from log entries from the standard system execution path.
Each log entry is then parsed to a log key and a parameter value vector. The log key sequence
parsed from a training log file is used by DeepLog to train a log key anomaly detection model
and to construct system execution workflow models for diagnosis purposes. For each distinct
key, DeepLog also trains and maintains a model for detecting system performance anomalies as
reflected by these metric values, trained by the parameter value vector sequence of k. During
detection, a newly arrived log entry is parsed into a log key and a parameter value vector.
DeepLog first uses the log key sequence to detect anomalies and then uses the parameter value
sequence to diagnose the detected anomalies further. The model utilizes Long Short-Term
Memory (LSTM) to capture the temporal dependencies between log entries. The LSTM block
remembers a state for its input as a fixed-dimension vector. The state of an LSTM block from
the previous time step is also fed into its following input, together with its (external) data input,
to compute a new state and output.
The LSTM block is efective because it can encode more complex patterns with respect to other
approaches such as N-grams. In the model’s application, given a sequence of log keys, a LSTM
network is trained to maximize the probability of having   ∈  as the next log key value as
reflected by the training data sequence. In other words, it learns a probability distribution
 (  =   |  −ℎ , ... ,  −2 ,  −1 ) that maximizes the probability of the training log key sequence
[
          <xref ref-type="bibr" rid="ref6">6</xref>
          ].
        </p>
      </sec>
      <sec id="sec-4-4">
        <title>3.4. Dashboard implementation</title>
        <p>Prior to initiating the deployment phase of our project within the infrastructure of the Google
Cloud Platform (GCP), our team meticulously designed and established an intricate dashboard.
This was conceived with the primary objective of facilitating the monitoring process and
presenting intricate data sets in a manner that is both intuitive and user-friendly. Such an
approach ensures that users, regardless of their technical expertise, can seamlessly analyze the
information at their disposal in a timely and eficient manner.</p>
        <p>After a comprehensive evaluation of available tools, we decisively selected Looker Studio for
this pivotal phase of our project. Our choice was influenced by Looker Studio’s reputation
as a premier tool in the realm of data visualization. It not only ofers the capability to create
dashboards and reports that are lucid and straightforward to interpret but also provides extensive
customization options. This adaptability ensures that the dashboard aligns perfectly with the
nuanced requirements of our project and the diverse needs of its end-users.
To elucidate further on the features we integrated:
• We incorporated two distinct drag-and-drop functionalities. These are designed to filter
data based on general metrics and anomalies. Such a feature empowers users by granting
them the autonomy to tailor their data viewing experience, aligning it with their specific
areas of interest or concern.
• Our dashboard boasts a time series visualization. On the x-axis, it delineates the data
column that signifies the log registration instance within our platform. Concurrently, the
y-axis portrays the number of daily logs. This strategic representation is indispensable
for stakeholders to discern patterns, trends, and potential anomalies over a specified
duration.
• We have also embedded a specialized table dedicated to highlighting the most recent
anomaly logs. This proactive feature ensures that users are promptly alerted to potential
discrepancies, facilitating swift corrective actions.
• Furthermore, we conducted an exhaustive analysis of the status codes inherent in our
dataset. This analysis is instrumental in ofering stakeholders a granular view of the
system’s operational health and its overall performance metrics.</p>
        <p>For stakeholders and interested parties seeking a tangible representation of our dashboard’s
capabilities, we direct them to Figure 2. Herein, a detailed and illustrative depiction of our
dashboard is presented, encapsulating its sophistication and utility.</p>
      </sec>
    </sec>
    <sec id="sec-5">
      <title>4. Analysis of results</title>
      <p>Deeplog has been deeply tested with literature datasets in works such as [17]. The model has the
advantage of not requiring abnormal logs to build a detection model using sequential vectors,
thus reducing the efort for model construction. It has also been highlighted that, unlike other
DeepLearning (DL) models, DeepLog can detect anomalies faster. Looking at the performances
on baseline log datasets, Deeplog obtains Recall well above 90% and, in some cases, even at
100% while not penalizing too much the Precision, making it a reliable tool to correctly genuine
anomalies but with a low False Positive rate. Unfortunately, we do not have labeled logs on
our use case data, meaning we must evaluate the model through unsupervised techniques. In
order to accomplish this, we set up an experiment where we remove one user at a time from
the training data and evaluate if the new user logs are detected as anomalies by the model.
In this way, the model works in Leave One Out Cross-Validation on the users [18], aiming at
identifying anomalous user behavior on the one left out.</p>
      <p>The underlying philosophy of the methodology we are inclined to employ hinges on a distinctive
premise: to gauge the eficacy of an algorithm in assimilating a user’s typical behavior, it is
imperative to juxtapose its understanding against activities manifested by other users. This
approach is predicated on the assumption that individuals, when observed across specific
dimensions, exhibit a marked variance in their behaviors. In essence, the uniqueness of individual
behavior patterns becomes the yardstick against which the algorithm’s learning is measured.
This hypothesis, while theoretically sound, required empirical validation to ascertain its practical
applicability. To this end, we embarked on a rigorous experiment. Our analysis encompassed
a substantial dataset comprising 47,604 unique log sequences. The results were illuminating.
The model, trained on the aforementioned principle, flagged all but 44 of these sequences as
anomalies. This outcome not only underscores the model’s proficiency in internalizing and
recognizing standard user behaviors but also its acumen in pinpointing deviations. Such
deviations, given their divergence from the established norm, are inherently treated as suspicious,
warranting further scrutiny.</p>
      <p>Furthermore, this experiment’s findings bolster the argument that individuals, even when
operating within similar environments or frameworks, tend to manifest discernible behavioral
diferences. Our model’s ability to discern these nuances and flag anomalies with such precision
is a testament to its robustness and the viability of the underlying concept.</p>
    </sec>
    <sec id="sec-6">
      <title>5. Conclusions</title>
      <p>Our endeavor is a comprehensive project that strategically integrates the capabilities of DeepLog,
capitalizes on the intricate LSTM architectures, and optimally utilizes the resources provided by
the GCP to innovate log management processes within CMSs. The overarching objective of
this initiative is to strengthen the fortifications of IT security, ensuring a more resilient and
robust digital infrastructure.</p>
      <p>By incorporating an advanced Artificial Intelligence system into our framework, we have
managed to streamline the traditionally complex tasks of classification and anomaly detection
within pivotal logs. The LSTM architectures, renowned for their ability to handle sequential
data, have proven invaluable in our quest. They facilitate the meticulous analysis of vast log
datasets, enabling us to discern and highlight even the most subtle suspicious patterns and
anomalous behaviors that might otherwise go unnoticed. Nevertheless, the unsupervised nature
of our approach could potentially be exploited by malicious users to camouflage their nefarious
activities within the log data.</p>
      <p>The GCP, with its renowned scalability and automation process, has been instrumental in
our project. Its capabilities have allowed us to manage and process substantial volumes of
real-time log data with unparalleled eficiency. The automation of log management processes,
a cornerstone of our project, has led to a significant reduction in manual interventions. This
not only minimizes the potential for human error but also liberates our team, allowing them to
channel their expertise toward more sophisticated security challenges.</p>
      <p>Furthermore, by harnessing Machine Learning models that are meticulously trained within the
GCP environment, we have been able to craft an intelligent solution. This solution stands out for
its ability to perform real-time anomaly detection, ensuring that security incidents are not just
identified but also addressed with alacrity and precision. However, we recognize the imperative
to implement measures to thwart potential exploitation by malicious actors, ensuring that our
system remains secure and reliable.</p>
      <p>Looking ahead, we envision several future developments:
• Continuous Learning: As cybersecurity threats evolve, so should our defenses. We plan
to implement a continuous learning mechanism where our system will constantly update
its knowledge based on new logs and emerging threat patterns [19].
• Integration with Other Systems: We aim to expand the compatibility of our solution,
allowing it to integrate seamlessly with various other CMSs and IT infrastructures.
• User Feedback Loop: To further refine our anomaly detection, we intend to incorporate a
feedback loop, allowing users to validate or dispute detected anomalies, thereby enhancing
the system’s accuracy over time.
• Advanced Visualization Tools: To aid in the interpretation of results and insights, we
are exploring the integration of advanced visualization tools that can represent complex
patterns in an easily digestible format.
• Enhanced Supervision: In light of the potential risks associated with unsupervised
approaches, we are considering the integration of supervised or semi-supervised mechanisms
to provide additional layers of security and mitigate the risks of malicious exploitation.
In summation, our project epitomizes the potential and eficacy of amalgamating DeepLog
and LSTM architectures within the GCP framework to redefine log management and elevate
cybersecurity standards. While recognizing the potential vulnerabilities associated with
unsupervised learning, we remain sanguine that a myriad of organizations, regardless of their scale
or domain, can integrate this solution to optimize their log management processes and fortify
their defenses against ever-evolving cybersecurity threats.
[12] Ghobakhloo, Morteza, et al. ”Industry 4.0, innovation, and sustainable development: A
systematic review and a roadmap to sustainable innovation.” Business Strategy and the
Environment 30.8 (2021): 4237-4257.
[13] Huba, Mikuláš, and Štefan Kozák. ”From E-learning to Industry 4.0.” 2016 International</p>
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[14] Park, So-Hyun, et al. ”Performance evaluation of open-source endpoint detection and
response combining google rapid response and osquery for threat detection.” IEEE Access
10 (2022): 20259-20269.
[15] Krishnan, S. P. T., Gonzalez, J. L. U., Krishnan, S. P. T., &amp; Gonzalez, J. L. U. (2015). Google
compute engine. Building Your Next Big Thing with Google Cloud Platform: A Guide for
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